Carburetors



G. E. RAYNOR July 1, 1958 CARBURETORS Filed May 21, 1956 INVENTOR. Gilberz E. Raynaw BY Q ATTORNEY Unite htates Patent fifice i atenteci July 1, 1958 CARBURETORS Gilbert E. Raynor, Tulsa, Okla.

Application May 21, E 56, Serial No. 586,100-

4 Claims. (Cl. 26144) This invention relates to an improved carburetor and is more particularly concerned with a carburetor having a variable venturi whereby the vaporized fuel passing therethrough is automatically proportionately measured and mixed with a moving stream of air or gas in accordance with the fuel-air ratio requirements of the engine utilizing the carburetor.

A carburetor for an internal combustion engine, or the like, is normally provided with a venturi section or throat for decreasing the pressure of the incoming air stream to siphon fuel, such as gasoline, from a supply reservoir into the air stream. The vaporized fuel is mixed with the air stream to provide for combustion thereof as required to supply the power for operation of the engine. Many present day carburetors, however, are provided with a venturi throat of a fixed size wherein the pressure drop or pressure differential created thereby is charged by the variance of the quantity of air being drawn through the carburetor by the suction force of the engine. This pressure change or variance in pressure differentials is utilized to vary the quantity of fuel being siphoned from the supply reservoir to vary the supply of fuel to the engine as required by the operation thereof.

The present invention contemplates a novel carburetor having a variable venturi section which automatically adjusts its throat area to the quantity of air required by the engine, and maintains a substantially constant pressure drop throughout the operating range thereof. In this manner, a more accurate fuel proportioning is pro vided for the engine operation. The variable venturi throat automatically maintains the most desirable fuel-air ratio for the various engine operating conditions by correctly balancing the venturi proportion and shape to the size of the fuel metering orifice, and the height through which the fuel must be siphoned from the supply reservoir.

The novel variable venturi is carried by a diaphragm which responds to pressure differentials for vertical reciprocation thereof. The reciprocally movable venturi member is provided with a siphon tube which extends downwardly into the fuel supply reservoir. Thus, as the siphon is moved vertically upward and downward within the supply of fuel, the distance through which the fuel must be lifted is varied, thus automatically controlling the rate of fuel flow into the air stream moving around the venturi portion of the carburetor. Furthermore, the size of the venturi throat is automatically varied by the action of the diaphragm to admit the proper quantity of air through the carburetor as required for varying the operating conditions of the engine. Thus, the fuel-air ratio is maintained at the most desirable level for providing an efiicient operation of the engine.

It is an important object of this invention to provide a carburetor wherein the venturi throat size is variable for automatically supplying the most desirable quantity of air to the engine as required by the variable operating conditions thereof.

It is another object of this invention to provide a novel carburetor wherein the fuel is siphoned upward from a supply reservoir to be dispersed with the air stream passing through the carburetor and the height through which the fuel must be lifted is controlled to supply Variable quantities of fuel to the air stream for maintaining the desired fuel-air ratio throughout the operating range of the engine.

It is still another object of this invention to provide a novel carburetor having a venturi section of variable throat size which is controlled by a pressure differential actuated diaphragm member to maintain a substantially constant pressure drop of the air stream passing through the venturi throughout the operating range of the carburetor.

It is a further object of this invention to provide a novel carburetor wherein the fuel is radially dispersed into the air stream in a manner which greatly facilitates the vaporization thereof and enhances the mixing of the fuel with the air stream.

It is a still further object of this invention to provide a novel carburetor having a variable venturi throat size which is of a simple and economical construction and of substantially increased efficiency in operation.

Other objects and advantages of the invention will be evident from the following detailed description, read in conjunction with the accompanying drawings, which illustrate my invention.

In the drawings:

Figure 1 is a sectional elevational view of the novel carburetor of the invention.

Figure 2 is a perspective view of the novel carburetor with a portion thereof cut away and having the spring member omitted for purposes of illustration.

Figure 3 is an enlarged sectional view of the fuel dispersing portion of the carburetor.

Figure 4 is a plan view taken on line 44 of Fig. 3.

Referring to the drawings in detail, reference character 10 refers in general to a carburetor comprising an outer housing 12 of substantially cylindrical configuration. The housing 12 is provided with an inwardly tapered portion 14 at the bottom thereof having a downwardly extending reduced portion or neck 16 at the lowermost portion thereof. The neck member 16 is provided with an outwardly extending circumferential flange member 18 having a plurality of circumferentially spaced apertures 29 therein for cooperating with suitable bolt members (not shown) to secure the carburetor adjacent a suitable engine, such as an internal combustion engine, or the like. A suitable throttle valve member 22 is disposed in the neck portion 16 in any well known manner, and an apertured cover member 24 is provided for the housing 12.

A substantially cone shaped member 26 is concentrically disposed Within the cylindrical housing 12 and is suitably rigidly secured therein to provide an annular space 28 therebetween. A transverse conduit member 30 extends diametrically through the lower portion of the cone shaped member 26. The conduit 30 is open at one. end 32 thereof and is provided with a centrally disposed aperture 34 to provide communication between the annulus 28 and a vertical stand pipe member 36. The stand pipe member 36 is suitably rigidly secured in an upright position on the conduit 3% and is concentrically disposed within the cone member 26.

A flexible diaphragm member 38 has its inner periphery fixed or suitably secured around the upper open end 40 of the stand pipe 36 and is supported therearound by a conical helical spring member 42 disposed around the outer periphery of the stand pipe 36 and secured to the conduit 39 as clearly shown in Fig. 1. A movable inner cone member 4-4 is secured around the outer periphery of the diaphragm 38 for vertical reciprocation thereby in response to pressure differentials as will be hereinafter set forth. A chamber 45 is thus provided above the diaphragm 44 and is sealed by the diaphragm from the pressure existing therebelow.

The inner cone member 44 is provided with a centrally disposed upstanding hub member 46 having a circumfer ential substantially cone shaped cap member 48 extending outwardly'therefrom and spaced slightly from the inner cone 44 to provide an annular fuel dispersal area 50 therebetween. -The hubmember 46 is providedwith a plurality" of circumferentially spaced longitudinal bores 52 extending therethrough into communication with the.

- 48 is moved out of contact with the outer cone'26. The

chamber'45 for a purpose as will be hereinafter set forth.

A central recessed portion 54 (Fig. 3) is provided at the 'lower end of the hub member 46 to receive a downwardly extending siphon tube 55 therein. The siphon tube 55 annular space 70 therebetween provides a venturi throat for the carburetor 10. As the inner cone 44 moves downward, the atmospheric pressure or air stream passes through the inlet 68 and passes through the venturi throat 70 for a reduction in pressure, and moves downwardly through the chamber 69 and throughthe throttle valve 22 for discharge into the engine. It will be apparent that the throat area of the venturi section 70 increases as. the inner cone member 44 moves downwardly within the .outer cone 26, and decreases as the cone member .44

is provided with a longitudinal bore 56 therethrough having a restricted portion or orifice 57 at the upper end thereof. A, plurality of transverse bores 58, preferably two as shown in Fig. 4, extend diametrically across the hub member in vertical alignment with the fuel dispersal space 50 fordirecting the flow of fuel from the siphon detail.

The annular space 28 provides a reservoir formain- V .taining a supply of fuel 60, such as gasoline or the like.

An annular shaped float member 62 is disposed within the annulus 28 and responds to, the fluctuation of the fuel level therein for actuation of a suitable valve member 64. The valve 64 is disposed within an inlet port 66 of the housing 12 to alternately provide and preclude flow of fuel therethrough into the reservoir for maintaining the desired'fuel supply therein for an eflicient operation of the carburetor lit. The outer cone member 26 islopen at the top 68 thereof and extends upwardly slightly from the cover member 24 to provide an inlet for the carburetor 10.

Operation The operation set forth herein relates to the carburetor 10 as utilized with an internal combustion engine (not shown). It will be apparent, however, that the carburetor is also applicable to utilization in other fields.

The carburetor 19 is suitably. secured adjacent theengine with the neck'portion 16 in alignment with the1intake pipe (not shown) of the engine as is well known in the industry. The flow of fluid through the neck pormove's upwardly therein. \Vhen the" cone 44 is sufliciently lowered to permit too great a quantitybfair 'to pass through the venturi 70 forthe requirementsof' the engine, the incoming air stream flowing into the chamber 69increases the pressure therein to reduce thepressure i differential across the diaphragm 38, so thatthe action of the spring 42 will urge the diaphragm upwardly.

The upward movement of .the diaphragm decreases the venturi throat size to reduce the quantity of air passing therethrough. The amount of lowering or raising of the movable cone 44 for control of the air quantity is gov- V erned entirely by the pressure differential across the diaphragm 38. The position of the throttle valve 22 and the speed of the engine determine the suction pressure within the chamber 69, as well known in the industry, and thereby control the pressure differential, acting on the diaphragm 38. Thus, the venturi throat size will beautomatically adjusted according to the engine operation requirements to supply the desirable quantity of air thereto at all times. In this manner, the pressure drop ofthe air passing throughthe venturi. throat 70 is maintained at substantially the .same level throughout the operating range of the carburetor and engine.

The fuel 60 within the reservoir 23 flows through the open end 32 of the conduit 30 and is directed into the stand pipe 36 through theaperture 34. .In accordance tion 16 into the engine is controlled by the throttle valve 7 I 22 in the normal manner. When the'engine is not running, the spring member 42 urges the diaphragm 38 in an upward direction until the outer periphery of the cone cap member 48 seats against the inner periphery of the outer cone member 26. Thus, no air can pass around the cap member into the engine. The opening 68 of the outer cone member 26 is open to atmospheric pressure, and this atmospheric pressure is communicated through the bores 52 into the chamber 45. Thus, the pressures acting on the top of the cap member4 8 and within the chamber 45 are equalized so that the vertical movement of the inner cone member 44 is not effected by changes in atmospheric pressure conditions, but is entirely controlled bythe flexing movement of the diaphragm 33.'

When the engine is started, a suction or low pressure is communicated from the intake pipe thereof to the in- When the pressure differ-j body of fuel confined therein.

with the fluid laws of. nature, the fuel within the stand pipe 36 will normally assume the same level as the fuel in the reservoir 28. The fuel reservoir is in communication with a supply of fuel, such as anautomobile gasoline tank or the like, through the inlet port 66.. The fuel level within the reservoir 28 is controlled bythe float member. 62 which controls the actuation of the valve 64 disposed within the inlet portion 66. Thusga sufficient supply of fuel is provided in the reservoir for its a an eflicient operation of the carburetor 10.

The siphon tube 55 extends downwardly within stand pipe 36, as hereinbefore set forth, and into the As the pressure of the air stream moving through the venturi'throat'70 decreases, the pressure at the outer periphery of the cap member 48 decreases. This lowered pressure is communicated through the fuel dispersal space 50 into the radial transverse bores 58 and through the orifice 57 to the bore 56 of the siphon tube 55. The atmospheric pressure within the chamber 45 acting upon the surface of the fuel in the stand pipe 36 is greater than the reduced pressure in the siphon tube and thus forces the fuel downwardly in thestand pipe and upwardly through the bore 56 of the spihon tube 55. The fuel moves upwardly through the orifice 57 and outwardly through the radial bores 58 into the fuel dispersal space 50. The fuel is vaporized by this action, and isejected from the dispersal area 50 around the periphery of the cap mom:

ber 48 intothe incoming stream where it is mixed therewith. This fuel-air mixture moves downwardly through the chamber 69, as hereinbefore setforth and is discharged therefrom into the engine for operation thereof.

manner the height through whichthe fuel from the stand It will be apparent that the siphon tube is' vertically. reciprocat ed within the stand pipe 36 simultaneously with vertical movement of the cone member 44. lnthis,

ing through the venturi throat '76. The lower the siphon S5 is disposed within the stand pipe 36, the less distance the fuel must be moved, the eby providing a faster rate of flow thereof through the dispersal space St; for mixture with the moving air stream. Similarly, the higher the siphon tube is disposed within the stand pipe, the greater the distance through which the fuel must be moved, and the slower the rate of flow thereof to the dispersal space. Thus, the fuel-air ratio is automatically maintained at the most desi able level for eflicient operation of the engine throughout the operating range thereof.

The diaphragm 38 provides for vertical reciprocation of the inner cone member 44 and the siphon tube 55 without the need for additional sliding seal members to preclude loss of the fuel from the stand pipe 36. Any spillage therefrom is directed back into the stand pipe by the diaphragm. Furthermore, the flexing action of the diaphragm for movement of the cone member 44 is substantially friction-free thereby providing an increased efficiency of operation thereof.

From the foregoing, it will be apparent that the present invention contemplates a novel carburetor wherein the flow of fuel into the air stream is provided by the pressure differential between the pressure acting against the surface of the fuel confined Within the stand pipe and the air pressure at the outer periphery of the fuel dispersing space. The pressure differential therebetween is maintained substantially constant by the vertical reciprocation of the inverted cone member 44 for varying the venturi throat size in accordance with the fuel mixture requirements of the engine, so that the rate of fuel flow into the air stream is controlled only by the height through which the fuel must be lifted in the siphon tube. The fuel siphoning height is regulated by the vertical reciprocation of the siphon tube Within the fuel supply, and this reciprocal movement is controlled by the operation of the engine and throttle valve. Any change of pressure in the engine induction system alters the pressure beneath the diaphragm to vary the venturi throat size for providing the desirable quantity of fuel mixture for discharge into the engine. Thus, the rate of fuel flow and quantity of fuel mixture delivered to the engine is automatically proportioned in accordance with the engine requirements throughout the operating range thereof.

Changes may be made in the combination and arrangement of parts as heretofore set forth in the specification and shown in the drawings, it being understood that any modification in the precise embodiment of the invention may be made within the scope of the following claims without departing from the spirit of the invention.

What is claimed is:

1. A carburetor comprising an outer housing member, an outlet port in the housing for discharging fuel mixture from the carburetor, a cone shaped member rigidly secured within the housing providing an annular fuel reservoir therebetween, an inlet port provided in said cone member for supplying air to the carburetor, an inner cone member reciprocally disposed within the first mentioned cone member, a siphon tube secured to the inner cone member for reciprocation therewith, means for communicating the fuel to the siphon tube, fuel dispersing means to discharge the fuel from the siphon tube to the incoming air stream and in proportion with the volume of the air stream, said movable cone member providing a variable venturi throat for reducing the pressure of the incoming air stream, pressure responsive means for reciprocating the inner cone member, and means to control the fuel level in the reservoir.

2. A carburetor comprising a substantially cylindrical housing member, an outlet port in the housing for discharging fuel mixture from the carburetor, a cone shaped member rigidly secured within the housing providing a fuel reservoir therebetween, an inlet port provided in said come member for supplying air to the carburetor, a

transverse conduit secured diametrically through the rigid cone member in communication with the fuel reservoir, a riser pipe in communicati; n with the conduit and concentrically disposed within the rigid cone member to receive a supply of fuel from the reservoir, an inner cone member movably disposed within the rigid cone member, a siphon tube carried by the inner cone member and centrally disposed within the riser member, pressure responsive means for reciprocation of the inner cone with respect to the rigid cone to provide a variable venturi threat for the carburetor, fuel dispersing means to discharge the fuel from the siphon tube to the incoming air stream in proportion to the volume of the air, and means to control the fuel level in the reservoir.

3. A carburetor comprising a housing member, a conical shaped member rigidly secured within the housing to provide a fuel supply reservoir therebetween, a second cone shaped member reciprocally disposed within the first mentioned conical member and concentric therewith to provide a variable venturi throat therebetween, a stand pipe rigidly secured concentrically within the first cone member, transverse conduit means provided in the first cone member for directing the fuel from the reservoir to the stand pipe, a siphon tube reciprocally disposed within the stand pipe, said siphon tube adapted to move simultaneously with the movable cone member, a spring urged diaphragm secured around the stand pipe to provide reciprocation for the movable cone member, a pressure chamber provided between the movable cone member and the diaphragm and in communication with atmospheric pressure for equalizing the pressures acting on the movable cone member, an inlet port provided for the carburetor for admitting a moving air stream to the variable venturi throat, fuel dispersing means for directing the fuel from the siphon tube into the air stream for mixing therewith at the venturi throat, said fuel dispersing means providing for proportioning of the fuel in accordance with the volume of air flowing through the venturi throat, and an Outlet port for discharging the fuel-air mixture from the carburetor.

4. A carburetor comprising a housing member, a conical shaped member rigidly secured within the housing to provide a fuel supply reservoir therebetween, a second cone shaped member reciprocally disposed within the first mentioned conical member and concentric therewith to provide a variable venturi throat therebetween, a stand pipe member rigidly secured concentrically within the first mentioned cone member, conduit means for directing the fuel from the reservoir to the stand pipe, a siphon tube reciprocally disposed within the stand pipe, said siphon tube carried by the movable cone member for moving simultaneously therewith, a spring urged diaphragm member secured around the stand pipe to provide reciprocation for the movable cone member, a pressure chamber provided between the movable cone member and the diaphragm, said pressure chamber open to atmospheric pressure for equalizing the pressures acting on the movable cone member, said atmospheric pressure in said pressure chamber acting on one side of the diaphragm to provide for a pressure differential thereacross for flexing of the diaphragm to provide the reciprocation for the movable cone, an inlet port provided for the carburetor to admit a moving air stream to the variable venturi throat, a plurality of radial bores in communication with the siphon tube for directing fuel therefrom into an annular fuel dispersing area whereby the fuel is vaporized for mixture with the air stream at the venturi throat, and an outlet port for discharging the fuel-air mixture from the carbureor.

Stewart Aug. 26, 1919 Weiertz et a1. Sept. 11, 1934 

